A simple route to produce tungsten carbide powders by high-energy ball milling and annealing

Tungsten carbide powders are extensively used to provide wear-resistance properties to metal-matrix coatings. Here, we propose a simple and efficient route for the production of WC powders from elemental W and C by room-temperature high-energy ball milling (HEBM) and subsequent annealing. WC powders were obtained, with a minor (< 4Wowt.) iron contamination, with only 4 h of milling of a W/C atomic mixture of 42/58 and 90min anneal at 1000 degrees C. This innovative and simple route to produce WC powders can be used to produce feedstock of reinforcing particles intended for wear resistant coatings. We explored the impact of the milling times (from 6min to 96 h), compositions (W:C ratio of 1, 1.17 and 1.38) and annealing conditions ranging from 4 h at 850 degrees C to 90 min at 1000 degrees C. The samples were analyzed for phase distribution and composition using XRD, SEM with EDX mapping, XRF and TGA. As expected, milling induces amorphization and introduces iron from the milling media. We show that an excess of C can efficiently suppress the formation of deleterious tungsten carbides.